Automatic telephone system.



A. E. STEVENS.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED OCT. 31. I913.

Patented June 20, 1916.

4 SHEETS--SHEET L m m V m A. E. STEVENS.

AUTOMATIC TELEPHONE SYSTEM.

APPLICATION FILED OCT. 31- I913.

Patented June 20, 1916.

4 $HEETSSHEET 2- Invenior A. E. STEVENS.

APPLICATION FILED OCT. 3I. I9I3.

Mtented June 20, 1916.

4 SHEETS-SHEET 3- I I I I 9 I I :0

' :I I I I I 1 I I I I I I l I 3 W as I I 2 I 3 29 I I as k I 12 I I I f I," I I I ll I' I I I l I Yb \15 1 f 4 I z T 48 I I a I I I [I I 50 I ibs 36g 18.; i a I MI 787 3 8 t I l "/1 33 III I 37 I I III III I I1 I I III IIIIII IIIII l I [HI/EJ2301- A. E. STEVENS. AUTOMATIC TELEPHONE SYSTEM.

APPLICATON FILED OCT. 31. 1913- 1,187,671 PntentedJune 20, 1916.

4 SHEETS SHEET 4- r. .m m V .m

UNITED STATES PATENT OFFICE.

ALTON E. STEVENS, OF QUINCY, MASSACHUSETTS, ASSIGNOR TO S. H. COUCH COMPANY,

INC., OF ATLANTIC, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

AUTOMATIC TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented June 20, 1!! 1'6.

To all whom it may concern:

Be it known that I. ALTON E. S'rnvnNs. a citizen of the United States of i'xmericarresiding at Atlantic, city of Quincy, in the county of Norfolk and State of Massachusetts, have invented a certain new and useful Improvement in Automatic Telephone Systems of which the following ia specificic tion.

My invention relates to that class of automatic telephone systems primarily designed for use in private installations, being limited in the number of possible connections obtainable: or in public service exchanges. where the number of stations does not exceed the limit of its ca mcity. I illusirate herein a system of one hundred and three lines capacity.

Among the objects of my inrention are the following --lo produce 1| system especially adaptable to the rco iirements of industrial plants. public institutirms. and the like; and of such simplicity as to require a. minimum amount of attention: also to ren der certain special classes of service whcreby the transaction of business may be trreatly facilitated.

The special features of my invention re side in1. Means whereby any station in a. system may become electrically associated with a trunk connected to another system, to permit of communication with a station not embraced in the first system. Means whereby a station in another system (public service or otherwise) may become electrically associated with any station of the system illustrated herein. 3. hleans whereby a series of special signal or call bells may be operated from any station for the purpose of locating a particular party or parties. 4. Means whereby a particular party may upon hearing a signal on said special signal or call bells. communicate with the station from which said bells were operated.

The apparatus illustrated in the accompanying drawings is the best means now known to me for accomplishing: the several objects of my invention. and its operation and scope will be understood from the following description and claims.

Referring to the drawings, Figure 1 represents diagrammatically the. circuits of two automatic selectors, included in the central station equipment. Fig. 2 represents diagrammatically thecircuits of a Sub-station telephone. Fig. 3 represents diagrammati calh. the special signal or general call" circuit. Fig. 4 represents diagrammatically the circuits of a monitors or manual op erators trunking apparatus. Fig. repre sents diagrammatically the circuits of a substation identical with that illustrated at Fig. its object being to facilitate description. Fig. 6 represents diagrammatically the circuits of a central station selector wherein the lockout and busy tone apparatus is omitted. Fig. "1' illustrates the operating side of an automatic selector. l ig. 8 is a. ide elevation of same Fig. i shows ll) connecting side of same.

same.

Referring to the mechanical elements of my invention illustrated in Figs. '2" l1), representing a elector. 1 is base c 1;:- uetic metal to whi l; is seemed. a bank or circle :2. of contact points 3. the points be ing arranged radially around a common center. and insulated from each other and from clamps 4. by which the bank is held integral. The bank of contacts is secured to the frame by two screws 8 9, which engage two posts as at 6: the posts also acting as spacings. 'l'wo alternate posts as 7. lUJextend up through holes in the base and cause the bank to register properly with the base. ()n the front of the base is a bridge 11, spaced from the base and secured to same by two legs l2. 13. A shaft 14 extends through a hole in the bridge. and a corresponding hole in the center of the base. the sh: it being in the center of the arc described by the bank contact points. At the upper end of the shaft It is a ratchet wheel 15 secured to the shaft by a taper pin 16. At the other end of the shaft is a boss 17 secured to the shaft by a long pin or rod 18 carrying a ball 51 of insulating;' material, the reason of which will be lat r explained.

Secured to thiboss 17. and insulated from same are tvo brushes 20, said brushes ill is a front elevation of being in the plane of the circle oi contacts. and designed to contact successively the corn tact points as 3. in the, contact bani; when the shaft is rotated. one brush contacting each side of the contactpoint. A. llat spiral clock spring crmtained in the tension cup 19 has its inner end secured to the shaft and its outer end secured to the tension cup, the tension on said spring tending to turn the shaft 14 and ratchet wheel 15. Fig. 7, clockwise, and the brushes 20 Fig. 9, counter clockwise, the latter being on the reverse side of the base. A stop 2:? engages the pin 18 when the shaftis at normal position, the brushes normally resting on contact point 184. The tension on the clock s'irin' is rc ulated by turning the tension cup 19, the same being secured by the screws An lnSlllated commutator brush 56 maintains a c1r cuit to the brushes 20 regardless of the posi- .tion of the latter.

The method of insulating the bank contacts and avoiding the clamp screws is shown at 54, Fig. 9. I

Secured to abent up car or lug 23 of the base 1, are two magnets; a selecting magnet 24 and a connecting magnet Adjacent to the free end of the selecting magnet 24 is an armature 26, hinged on the shaft 14 by means of two bentears through which the shaft extends. The armature is held in, or returned to its normal position against a back stop 31, by a spring 30; said spring back stop and spring 41 being assembled in a unit and secured to the base 1.

The armature 26 carries at its outer end a pawl 27, designed to engage the ratchet wheel 15 and step it around one tooth each time the said armature is attracted by the selecting magnet 24, each step of the ratchetwheel causing the brush 20 to advance to the next successive contact point in bank 2. In its normal position the pawl 27 is held out of engagement with the ratchet wheel 15 by the guide 29 riveted to the bridge 11. Upon completion of a forward step of the ratchet wheel 15, the pawl 27 engages a bent up lug 28 of the bridge 11; said lug locking the pawl intothe ratchet wheel, and prevention the ortia ot' the latter from throwing the pawn out of the tooth. A small spring, which for the sake of avoiding con fusion is not shown, tends to hold the pawl 27 against the ratchet wheel 15. The armature 26 carries at its other end, a curved extension or arm 48, the reason of which will be explained later.

A. spring dog 33 having an aperture through which the edge of the ratchet wheel 15 protrudes, engagesthe teeth of said ratchet wheel and holds same in each successive step to which it is moved by the selecting mag net 2 The spring dog 33 is clamped to a frame 34, which is secured to an extension of the bridge 11; said nae being pivoted under the head of a shaft 35 and slotted under the head of screw by which it is secured to the bridge 11, the slot permitting of its being moved to adjust the tension of the spring dog 33 against the ratchet wheel 15. The spring dog 33 is slotted under its clamp to permit of a forward and back adjustment in relation to the ratchet teeth, so that it may just drop into a tooth when the selecting armature pawl has reached the limit of its forward stroke.

The shaft 35 extends down through the extension oi the bridge 11, and through a hole in the base 1; an armature 37 operated by connecting magnet 25 being pivoted thereon. A cotter pin 53 through said shaft 35 keeps it in place.

An arm 42 of armature 37 carrying an insulation 44 extends down through a hole 46 in the base 1, and operates a groupof con tact springs assembled in a unit 47 and secured to base 1, said springs being shown in circuit in Fig. 1. A second extension or arm 38 of armature 37, carries a dog 39 pivoted at its outer end; said dog being bent upward and its end 40 protruding through the aperture in spring dog 33, directly under the ratchet wheel 15. \Vhen the magnet 25 is energized and attracts its armature 37, the dog 3-) is drawn back through the aperture in spring dog 33, a notch in end 40 engaging the vertical side of the aperture in the spring dog by reason of a spring 42, which moves said dog 39, and when the magnet 25 is deenergized and releases its armature 37, the end 40 of dog 39 kicks the spring dog 33 out of engagement with the ratchet wheel 15 and holds it there, and the ratchet wheel is per mitted to move freely back to normal position. The spring 41 holds armature 37 in, or moves it to normal position. The back movement of armature 37 is limited by the engagement of insulator 44, with the side of the hole 46, and its forward movement by the end of magnet 25.

back side of base 1; its insulated springs- 181, 182, shown in circuit in Fig. 1, being brought into contact with each other as are also springs 381. 382 and there held, by insulation 51 on the end of pin 18, when the latter is in normal position against stop 22,

the two sets of springs being insulated from each other.

The brush 20, contact points 141, 184, 185, 186, 187, and magnets 24, 25 are shown in circuit in Fig. 1. The relays 120, 129, 166, Fig. 1, having no mechanical association with the selector elements as represented in Figs. 7, 8, 9, 10, may be mountediseparately. or on the same base.

A connecting jack strip 48 of insulating material, secured to lug of base 1, and carrying plugs as 49, which may engage female jacks or plugs in a convenient selector support, provides a ready means for connecting the selector wiring to the other circuits. of the system.

The hole 50 in selector base 1, is for a wiring cable which connects together the electrical elements on the two sides of the selector base. The base 1, being of magnetic metal, forms part of the magnetic circuit of magnets 24, 25.

All of the lines of a system are multiplied into each selector by being connected to the bank contact points as 3," each line being connected to the same point in each selector bank.

Having now explained in detail the operation of the mechanical parts of my in vention, I will proceed with a tall explanation ofits complete operation.

Each telephone station is supplied with an automatic impulse transmitter, the cir cuits of the station being arranged as shown in Fig. 2. The impulse ransmitter may be any one of several well known types, the. special requirements being as follows :--1- Selective impulses are automatically made by causing spring 107 to contact 108 a pre determined number of times. 2-Normally, spring 103 contacts springs 105, 104, but during the time selective contacts are being made between 107, 108, the spring 103 is out of contact with 105, 104, and in contact with 106. After the last selective contact, the spring 103 is moved to normal position again. \Vith these requirements in mind I will refer to Figs. 1, 2, 5, and also to mechanical details in Figs. 7, 8, 9, 10. e will not consider Fig. 4 at present, by joining Wire 147 to 150, and 203 to 213, the cir cuits from Fig. 5 become identical with those from Fig. 2. For convenience, if ,the wires intersected by dotted line A be joined to those inserted by dotted line B a continuous diagram of circuits will be presented.

In making a call from station Fig. 2 to station Fig. 5, wh

ich we will call No. 4,

, the receiver 101 is removed from hook 102,

thereby causing spring 113,,and the automatic impulse transmitter operated to cause 107 to contact 108 four times; the spring 103 contacting spring 106 112 to contact spring 129 to negative battery during this period. A selecting relay 120 of the central apparatus associated with Fig. 2 is thereby energized four times over the following circuit;-from negative battery 121, through relay 120, wire 119, springs 108, 107, 106, 103, wire 117, springs 112, 113, wire 111, to positive battery 109. Relay 120 thereupon attracts armature 122 four times and causes selecting magnet 24 to become energized a like number of times by causing spring 124 to contact 123, the circuit being as follows:from negative battery 121 through selecting magnet 24, springs 126, 125, 124, 123, to positive battery 100; the selecting magnet 24 thereby causing the brush 20 to step to the fourth contact from normal, or 141. As the selecting impulses cease, spring 103 is moved away from spring 100, and back to normal position in contact with 105, 104, and establishing the following connecting relay circuit :-fro1n positive battery 109 through wire 1 1, springs 113, 112. wire 117, springs 103, 105, transmitter 118, receiver 101, wire 128 connecting relay 121; the connecting thereby energized and attracing its armature 130 and causing .ng 131 to contact spring 132 and establishing ai-onnccting magnet circuit locally from positive battery 109 through connecting magnet 25, springs 132, 131, to negative batter 121. The connecting magnet 25 upon being energized thereby attracts armature IE7 and by causing spring 125 to contart 1 54 and 335 to contact 135, completes atalking circuit, shown in heavy lines, from positive battery 109, through wire 111, springs 113, 112, 10 105, transmitter 118. receiver 101, wire 128, condenser 136, springs 1:35. 335, 321, 124, 12.5, 131, 138, 139, wire 140, to brush 20 and to bank contact 141, to which is connected a multiple wire 142 of the station shown at Fig. 5.

To signal the called station a ringing button now pressed causing spring 156 to contact springs 157, 158. the result being to again energize relay 120, as for selection, the circuit being as followw from negative battery 121, through relay 120. wire 110,

relay 1230 becoming springs 156, 104, 10 112, 113, wire' 346, where the circuit springs 400, 401, 402, 403 together while the button 156 is pressed; the remainder of the current flowing from point 346 to Wires 147, 150, direct current ringer 151, springs 152, 153, wires 154, 354, springs 382, 381, 401, 400, 402, battery 121; the ringer 151 being thereby operated and notifying the called party.

In response to the signal the receiver 214 is removed from hook 215 thereby separating springs 152, 153, and opening the ringer circuit, and connecting together springs 208, 209. The two stations are now in condition to permit of conversation, the transmitter at each station receiving its operating current through its individual circuit above described as the connecting relay circuit, and the two stations being united as regards voice produced currents from wire 128 through condenser 136, springs 135, 335, 324 124, 125, 134, 138, 139, brush 20, contact 141, bank wire 142, springs 144, 145, wire 146, to Wire 147, and thence to the called station.

Voice produced currents in either transmitter will cause variations of current through the above circuit in a well known manner, and conversation can be carried on.

Replacing the receiver 101, at the calling station, upon its hook 102, causes the connecting relay circuit to be interrupted by separating springs 112, 113, and the connecting relay 129 upon being denergized permits springs 131, 132 to separate thereby deenergizing the connecting magnet 25, and causing the selector mechanism to return to normal'position as already explained in connection with Figs. 7, 8, 9, 10'.

The springs 181, 182, simply short circuit the condenser 136, when the selector is in normal position, to permit of the passage of direct current from a calling station for signaling and also to facilitate the passage of voice produced currents from the calling station, which pass through the calling station condenser.

I will now describe the lockout and busy tone feature of my invention. When two stations are connected for conversation positive battery 109 is connected to the multiple bank wires as 190, 142 of both stations, and hence to the contact points of those stations, through the circuits of the called station; the circuit being as follows :from

positive battery 109, through wires 203, 213,

springs 203, 209, 207, 20c, transmitter 205, receiver 214, wires 150, 147, 146, springs 145, 144, to bank wire 142, and point 141 of the called line, and through brush 20, in contact with said point 141, springs 139, 133, 134, 125, 124, 324, 335, 135, wire 179, to multiple bank wire 190 and contact point 186 of the calling line; thus a third station calling either of these stations would find positive battery on the bank contact points of both busy lines. With this condition in mind, let us suppose that station Fig. 5 is one of the busy pair, and station Fig. 2 is a third station desiring connection with a busy station. A. normally open circuit extends from brush 20 back over wire 140, springs 139, 138, 134'. 133, lockout relay magnet 166 to spring 168. A call made from station Fig. 2 would move the brush 20 into contact with the point 141. of the busy line, said brush finding positive battery thereon. When the brush 20 comes to rest and current flows through connecting relay 129 to supply the transmitter at the calling station, 129 becomes energized, the armature 130 causing spring 131 to contac spring 168. and completing a lock-out relay circuit from the positive battery on point 141 through brush 20, springs 139, 138. 134. 133, magnet 166, springs 168, 131, to negative battery 121, said magnet 166 attracting armature 167 and operating its contact springs as followsr-spring 164 contacts 165; 130 contacts 162; 138 breaks from 139. and contacts 163; th result being that first a holding circuit is established from the positive battery on contact 141, through brush 20, springs 139,162, lockout relay magnet 166. springs 168, 131, to negative battery 121; the lockout relay magnet 166 remaining operative until the calling selector is released thereby separating springs 168, 131; or until the called busy line ceases to be busy, thereby removing positive battery from point 141.

It is to be noted that the lockout relay 166 depends on its lockout relay circuit for its operation as explained above; said circuit requiring contact between springs 134, 133. Now, both the lockout relay magnet 166 and the connecting magnet 25 depend upon the operation of connecting relay 129 for the completion of their circuits. and it will be evident that the said lockout relay magnet must close its local holding circuit by causing contact between springs 139, 162, before the initial energizing circuit is interrupted at springs 133, 134. There is ample time for this however, as the spring 131 contacts spring 168 before it contacts 132. and 166 iS a quicker acting magnet than 25. and has less work to do, as 25 operates certain mechanical parts or the selector, and springs 139. 162. being very close together, the holding circuit contact is made quickly; whereas the magnet 25 has to move spring 125 into contmrt with spring 134 before 134 breaks from 133'.

It may be noted here that if a call is made to a non-busy line the lookout relay magnet is render d inoperative under all subsequent conditions by the opening of its initial energizing circuit at springs 133,

131. The lockout relay also closes a busy tone starter circuit from negative battery 121 through springs 101, 165, to common bus-bar 170, continuing through primary 171 of a busy tone coil, interrupter 172, 173 to positive battery 109.

The interrupter 172, 173 operated by the core of the coil alteinately attracting the armtaur 1.73 a ay from point 172, and releasing same in a manner well understood; the inteiruptions of current being repeated by induction into the secondary winding 174., and affecting the receiver at the falling station to notify the calling part\' that the called line is busy.

The bus tone circuit may be traced from positive battery 109 through winding 174, condenser 173 to common bus-bar 170, wire 17?, springs 1m, 129;, cu, 125, 12 1, 324, 325, 13;). coiulenser 130, wire 128, receiver 101, transmitter 118. springs 105, 103, 112, 113, wire 111, to positive battery 109, the tone being audible in the receiver 101.

1. will now explain the method of obtaining connections to other systems, said other systems being ot the common battery type; wherein resides the first and second features of my ii HiiiiUii. Calls from any automatic teic one may he made direct to a trunk leading to an outside system. while calls from the outside system to an automatic ti-hmhonv are revived by a monitor who completes the conm-ction to the wanted station. The monitons apparatus consists of a regmar automatic telephone as shown in Fig. 5 and in addition the special apparatus shown in Fig. 1 consisting of a repeating coil 228, .220. a trunk relay 230, a special key 217 of the double listening type, and a ringer and condenser 231 bridged across the trunk 2213, 227, to operate on incoming calls. To make a call from a station as Fig. 2 to the trunk 221'. .227, leading to an exchange of the common battery type, th automatic impulse transmitter is operated to call point 185, Fig. 1, which is the representative hank contact of the outside connection. The springs 181, 18:2, are so adjusted that they do not break contact when the brush 20 is moved to this trunk point 185. The result ing trunk relay circuit may be traced from positive battery 10!), through wire 111, sl'irings 113, 112, 103, 105, transmitter 118. receiver 101, wire 129. springs 182, 181, wire 17.). springs 13:), 337', 3521, 121. 125. 134, 138, 1:10, to brush :20 and contact hank wire 18S, wire 1111, trunk relay 2 -10 and repeat ing coil winding 2120, in multiple, wire 233, to negative hattciy 121. Voice produced currents in this circuit are repeated from winding 22!! to winding of the repeating coil by reason of their inductive relations, the condenser 275 facilitating the transmission.-

Current flowing through the circuit above described causes trunk relay magnet 230 to become energized, and attract armature 224, thereby closing a signaling circuit between trunk wires 220, 227, which may lead to a conventional common battery exchange, and have connected to them the usual signaling and connecting devices; the circuit being from wire through winding 228, wire 231. contacts 225, 221 to wire 227; thereby operating the central station devices in the same manner as bridging a telephone across these trunk wires would do. Conversations may now take place between the automatic systennnud the common battery central, or any station in the common battery exchange, which may be connected to the trunk 220, 227, through the repeating coil windings 228, 229, and condensers 275.

Replacing the receiver 101 on its book 102 at the calling station, releases the connection in a manner already explained, and trunk relay 230 becomes i'lci nergized and releases armature 221, thus opening the trunk circuit to the :ommon battery eX- change by separating contacts 224, 225.

A call from the common battery exchange to a station in the automatic system illustrated is accomplished as followsz-Signaling current from the common battery exchange on trunk 227, operates the ringer at 234 which is pern'ianently bridged across the trunk through a condenser. A monitor in response moves key 217 in the direction indicated by the arrow, the key being pivoted on the ccntbr 218 and carrying aninsulation 219 which moves springs 149 and 212 out of contact with 148, 211, and into contact with 23:, 2313; thereby severing all connections 1' rom station Fig. 5 to the automatic system, and connecting the station as an independent telephone directly to the trunk wires 220, 227, and using current from the common battery exchange to render the station Fig. .3 operative; the circuit being as tollowsr--from wire 220 through wire 232 springs 30. 212, wire 213, springs 208, 209, 207, 206, transmitter 205, receiver 214, wire 150, springs 149, 235, wires 222 and 227; the station Fig. 5 being to all intents and purposes a conventional common battery telephone connected in the regular manner to the central exchange,'and conversation can be carried on between the common battery calling station and station Fig. 5. The monitor at station Fig. 5 upon learning that connection to a particular automatic station is desired, moves key 217 in a direction 0pposite to that indicated by the arrow, thereby permitting springs 149, 212, to break connection with 236, and to connect with 14-8, 211, thereby establishing normal connections between station Fig. 5 and its associated selector illustrated in Fig. 1; also by connecting together springs 220, 221, maintaining a holding circuit to hold the supervisory devices operative at the common battery exchange while the call is being transferred; the means being the short circuiting of normally open contacts 221, 225, and the result being the same as when the relay 230 is energized. The monitor now automatically calls in the regular manner the desired station and tells the answering party to call the trunk, which they proceed to do in the regular way, as explained above, and upon obtaining the proper connection causing the trunk relay 230 to become energized which by closing contacts 224, 225 holds the trunk independent of the connection between springs 220, 221, of the monitor key 217. When the .wanted party completes connection to the trunk and operates the trunk relay, the monitor is aware of the fact by the lighting of the lamp 405; the circuit being as follows:--from negative battery 121 through wirc 233, contacts. 4-00, 107, lamp 405; to wire and positive batterv 109. The monitor now moves her key 217 back to normal position and has no further supervision over the call, the conditions being the same as for an outgoing trunk call, originating in the automatic system.

I will now explain the special signaling means embodying the third and fourth features of my invention.

Referring to Fig. 3, a series of bells 202, connected in multiple, are located in different zones in a plant, so that one or more of the bells may be heard from any part of the plant. \Vhen a particular party is wanted. as a superintendent for instance, who may leave his usual station and be in any part of the plant, the party desiring to communi cate with him from say station Fig. 2, operates his station to connect with bank contact point 187, and presses his ringing button as in making a regular call. Ringing current is sent out over the regular circuit from positive battery 109 to brush 20 and contact 187, bank wire 1S9. Wire 1113, general call relay 195 to negative battery 121: 195 becoming energized and attracting armaturc 196. which by causing contact between springs 197, 198, completes a bell circuit from negative battery 12!. through contacts 198. 197. wire 201, bells 202, wire 200 to positive battery: the bells 202 being thereby operated. The wanted party, upon hearing his call. steps to the nearest telephone and calls the same number as the cal 1- ing party, thereby connecting his station to a bank contact which is muliipled by the multiple bank wire 18$ to the correspondin bank contact of tlic calling. station. The two may now converse and the wanted party has been quickly located by the calling party, although he was at the line @1121 place unknown to the calling party.

By arranging a code 01' ignals For the general callbells, the scrv may be extended to include several parties, each one responding when his particular signal is rung.

It to be noted that the springs 181, 182, Fig. 1, are separated when the brush 20 is stopped to any point l'ieyond the trunk point 185, the general call relay circuit, except when the ringing button is pressed, including in series the condenser 136; otherwise the relay 19.3 would remain energized as is the case with the trunk relay 230 and the bells 202, ring continuously.

In many cases the lockout and busy tone features are not 'anted. Fig. 0 shows the arrangement of the selector circuits where all apparatus required to obtain privacy is omitted, the circuits shown being the same as illustrated in Fig. 1, except for such changes as are made necessary by the omission of the lockout and busy tone apparatus.

To ailord a better comparison between Figs. 1 and 0, the corresponding elements in Fig. 0 are numbered the same as in Fig. 1. Connecting the wires 111, 119, 128, to wires of same number in Fig. 2, the selecting relay circuit may be traced as follows from positive battery 109, through elements 111. 113, 112, 103, 106, interrupter 107, 108, wire 119, selecting relay 120, to negative battery 121. The connecting relay circuit from positive battery 109 through 111, 113, 112, 117, 103, 105, 118. 101, 12s, connecting relay 129, to negative battery 121. The connecting magnet circuit from positive battery 109, through connecting magnet 25, springs 132, 131. to negative battery 121. The ringing circuit from positive battery 10.) through springs 12-1, 123, 125, 13%, wire 1-4.0 to brush 20. Th talking circuit. same as the connecting relay circuit from positive battery 10%), through the station Fig. 2, to wire 12 then through condenser 130 (181, 182 being separated) springs 13?, 335, 32.4, 1235. 123. 134, wire 140 to brush 20. The ex planation oi the mechanical operation would be the same as for a systcni with the lockout and busy tone.

Having now fully described my invention what 1 claim is? 1. In an automatic telephone system, a plurality of substations; a n'ionitors station: individual lock-out means for each substation; a trunk line from another tcm terminating at said monitofs station: means whereby incoming calls'over said trunk line may be controlled by l monitor: means. beyond the control of r id moni tor, whercby any one of said substations may estab ish communicable relations with said tr? line: and means whereby any other oi said substflions, in attcnil'iting to enter into comuiunicable relations with said trunk line, while said trunk line is in commuuication with said one.will automatically operate its own lock-out means.

2. In an automatic telephone system, a substation; a selector for said substation comprising a lock-out relay; a lock-out relay circuit; a connecting relay; a connecting magnet; means whereby said connectingrelay may close said circuit; means whereby said connecting relay shall control said con necting magnet; means whereby said connecting magnctmay, through the agency of said connecting relay, open said circuit; and an auxiliary holding circuit for said loclcout relay and controlled thereby, whereby said lockout relay may remain energized if said lock-out relay circuit be opened through the agency of said connecting magnet.

13. In an automatic telephone system, a substation; a. selector for said substation comprising a. lock-out relay; a connecting magnet; a connecting relay; means whereby said connecting relay shall control the energization of both said magnet and said lockout relay; a lock-out relay circuit; means whereby said magnet may control said lockout relay circuit; meanswhereby said connecting relay may simultaneously operate to energize said magnet and said loclcout rclay; means whereby said lock-out relay may operate its armature before said magnet has opened said circuit; and an auxiliary holding circuit adapted to maintain the energization of said lock-out relay after said magnet has opened said lock-ont relay circuit.

4. In an automatic telephone system, substations; a selector for each substation comprising a bank of line terminals; :1 series of line-wires suitably connected to said terminals; means whereby talking intercommuni ration may be established over any one of said wires; a locleout relay; a connecting relay; a. connecting magnet; a lockout relay circuit depending on any one of said wires in use for its operation; means whereby said connecting relay may close said circuit; means whereby said magnet may open said circuit, when closed by said connecting relay; and an auxiliary holding circuit adapted to maintain the energization of said lock-out relay when said magnet has broken said lockout relay circuit.

5.'In an automatic telephone system, a. plurality of substations; an automatic central station; connectors between each of said substations and said central station; selective means for each of said substations adapted to permit private signaling therebetween; a ringing relay connected in multiple with each substation special selective means for each of said substations whercby' any of said substations may operate said ringing rela and independent signa ing means, automatically operated through the agency of said rela Y and adapted to simultaneonusly signal all of said substations.

6. In an automatic telephone system, a

plurality of substations; for each substation a. selector with a bank of line terminals;

for each substation. a line wire suitably connected with said terminals; means whereby any of said substations may alternately employ any of said line wires to privately call and communicate-with the substation permanently connected thereto; a general call wire controlling independent signaling means and adapted to simultaneously signal all of said substations; means whereby any of said substations may operate the general call wire; and means whereby any other of said substations may employ said general call wire for non-private conversation with the calling substation.

7. In an automatic telephone system, a plurality of substations; a common battery therefor; a ringing relay; signaling means, independent of said substations. for simultaneously signaling all of said substations, said means being connected with said battery and means whereby any of said substations may cause said relay to automaticall; operate said signaling meauss 8. In an automatic drain-one system, a pluralit of substatx" elephone lines theret'or and adapted for private inter-com municmi'imi; a general call line for the simnt taneous signaling of all of said substations, said line being adapted for non-private conr municalion between said substations; means whereby any of said substations may oper ate said general call line for such signaling: and alternative means whereby the answering substation may employ either private or llfill'pllVtltfi means of communication.

U. In an automatic telc 'ihone system, a plurality of substations; a series of line wires. one for each substation, adapted for private comnumication between said substations; a general call wire adapted for use in sinuxltaneously signaling all of said substations: n ans whereby any of said substations may operate said call wire for signaling: and means whereby said call wire may, without the employment of any of said line wires, be used for non-private communication between any of said substations.

10. In an automatic telephone system, a plurality of substations; means, within the control of each substation, for private communication between said substations; and alternative means whereby any of said substations may simultaneously establish relations for communication with all of the rest of said substations.

1l. In an automatic telephone system, a plurality of substations; means, within the control of said substations, for establishing private communication therebetween; a general call circuit adapted for simultaneously signaling all of said substations; means whereby any of said substations may operate said circuit; and means whereby said circuit may be employed by all of said substations for general conversation.

12. In an automatic telepl'ione system a plurality of substations; telephone lines therefor; private calling means for each substation; signaling means, independent of said calling means, for simultaneously ig naling all of said substations; and means whereby any of said substations may operate said signaling means.

13. In an automatic telephone system, a plurality of substations; a plurality of selectors for said substations, each having a bank of line terminals; a series of line Wires suitably connected with said terminals and adapted for inter-co mmunication; a general call circuit adapted to simultaneously signal all of said substations, said circuit being suitably connected to each selector; means whereby any of said substations may operate said circuit; and means whereby the subsequent conversation may take place over said circuit.

14. In an automatic telephone system, a

lective communication between said substations; a common battery for said lines; an independent circuit equipped with means for simultaneously signaling all of said substations, said circuit being connected with said battery; and means whereby said circuit may be employed for conversation between said substations.

15. In an automatic telephone system, a plurality of substations; a plurality of selectors therefor, each having a bank of line terminals: a private line wire for each substation suitably connected to its terminals; means whereby conversation between two of said substations may take place over the line wire of the called substations; a general call line wire suitably connected to certain of said terminals; IIIHIIS whereby all of said substations may be simultaneously signaled over said 'general call wire; and means whereby the subsequent conversation may employ said general call line wire.

16. In an automatic telephone system, a plurality of substations; telephone lines therefor; a common battery for said lines; means whereby said substations may enter into private inteoconununication; a general call circuit; independent signaling means connected with said battery and adapted for operation through the agency of said ciruit; means whereby any of said substations may employ said circuit to perate said signaling means to (all all of said sul'istations; and means whereby said general call may be answered at any of said substations.

17. In an automatic telephone system, a plurality of substations; telephone lines and a common battery therefor; selective means whereby private inter-communication may take place between any of said substations; a general call circuit; independent signaling means connected with said battery and adapted to be operated through the agency of said general call circuit; means whereby any of said substations may employ said cirsuit to issue a simultaneous general call; and means whereby any other of said substations may employ said circuit for non-private conversational purposes, in answer to said call.

18. A private telephone station, a monitors station; connectors for said stations; a trunk line terminating at said monitors station; means whereby incoming communication from said trunk line to said private station is under the control of said monitors station; means whereby outgoing communication from said private station to said trunk line may be beyond the control of said monitors station; and means for notifying said monitors station that said trunk line is in use.

19. A private telephone station, a monitors station; connectors for said stations; a trunk line terminating at said monitors station; means whereby said monitors station may operatively connect said trunk line to said private station; automatic means, beyond the control of said monitors station, whereby said private station may be operatively connected to said trunk line; and means, at said private station, for interrupt ing all connection therefrom to said trunk line.

20. In an automatic telephone system, a monitors station; a substation; necessary connectors therefor; a trunk line terminating at said monitors station; means whereby said monitors station shall control incoming calls from said trunk line; and automatic means, beyond the control of said monitors station, whereby said substation may short-circuit said monitors station to operatively connect to said trunk line.

21. In an automatic telephone system, a plurality of substations; a monitor's station; connectors for said substations and said monitors station; a trunk, line terminating at said monitors station and adapted to form electrical connection with any of said substations; means whereby said monitors station may handle incoming calls from said trunk line; and automatic means, beyond the control of said monitor's station, for shortcircuiting said monitors station for outgoing calls from any of said substations.

22. In an automatic telephone system, a plurality of substations; a monitors station; a trunk line from another system terminating at said monitors station; manual means whereby incoming calls over said trunk line are controlled by said monitors station; means, beyond the control of said monitors station, whereby any of said substations may establish communicable relations over 'nnk line and automatic means for Ag said monitors station that said 1:: is in use. In an automatic telephone system, a n; a inonitors station; a trunk retrunk line; and means, beyond the t of said monitors station, whereby mid amt; relay may automatically cause ALTON E. sTEvENs.

Witnesses:

S. L. BENNETT, A. M. PLUNKETT. 

